MISSISSIPPIAN FOSSILS 



97 



The Commoner Fossils 



PLANTS. Poorly preserved plant remains occur throughout the Mississippian. Their 

 identification, when it can be achieved at all, is a matter for a specialist. The logs, tree- 

 trunks, and twigs of our Mississippian beds are in general so similar to those of the Pennsyl- 

 vanian that the discussion of Pennsylvanian plants (chapter 8) may be used for both. 



Tiny spore coats of unknown plants, already mentioned in chapter 6, are also found in 

 the Mississippian. 



PROTOZOA, Foraminifera undoubtedly existed in our Mississippian seas but as yet we 

 have no record of them. 



PORIFERA. Sponges were present in the Mississippian seas of Ohio. The only ones for 

 which we have a record are those which burrowed into the shell of other organisms, making 

 holes and tubes. These may be simple or branching. In some specimens the shell may be 

 dissolved away, leaving only the mud fillings of the sponge burrows. 



ANTHOZOA. Corals are generally rare in our Mississippian rocks and we know of no 

 coral reefs of this age in Ohio. Several species of Zaphrentis (see fig. 163) are present in 

 the Waverly and Maxville. All are smaller and more delicate than the Devonian species. 

 Honeycomb corals (see fig. 154) are very rare. 



CONULARIDA. Some of the finest speci- 

 mens of conularids have been collected from 

 Ohio Mississippian rocks. The two common 

 species, C. micronema (fig. 235) and C. new - 

 berryi (fig. 236) can be distinguished by the 

 features shown in the figures. 



BRYOZOA. A few bryozoans occur in 

 our Mississippian rocks but their identification 

 is difficult because of poor preservation. Spe- 

 cies of Fenestrellina (see fig. 98) or a related 

 genus occur in the Cuyahoga, Logan, and 

 Maxville formations. 



Fig. 235 



Fig. 236 



BRACHIOPODA . The most abundant individual fossils in our Mississippian rocks are the 

 brachiopods. They are remarkably varied in size and appearance but only 19 genera may be 

 considered common. They may be identified from the following key. For further information 

 on Brachiopoda, see Hyde (1953). 



Key to the Commoner Mississippian Brachiopods of Ohio 



(see p. 4 for use of keys) 



1. a) Shell smooth or with concentric markings only 2 



b) Shell with radiating and concentric markings 6 



2. a) Beak on margin of shell 3 



b) Beak near center of shell Orbiculoidea 



3 . a) Height greater than width 4 



